Field of the Invention
The present invention relates to a front disc of a filter insert.
A disc is known as a part of a filter insert from DE 44 16 577 A1. The FIG. 6 of this document discloses a disc which in its area adjacent to the aperture is continuously slightly thickened, and is thermally welded in this thickened area with the sealing. The welding in this case extends across approximately the total surface area of the thickened area inwards in the area of the aperture, the sealing projects such that after plugging the disc onto a connection piece it is compressed and upset whereby the required sealing effect is attained.
With this known disc sealing combination, with only little effort, a sufficiently safe sealing could be attained, however, it has been found in practical operation that during the manufacturing relatively small tolerances have to be maintained in order to ensure a safe sealing on the one hand, and on the other hand, to avoid a too tight fit of the disc on the connection piece, and that furthermore it is desirable to make the manufacturing of the disc even more economical by accelerating the welding process when connecting the disc and the sealing.